Testing Patterns of Association between Brachiopod Bioclast Deposits and Stratigraphic Discontinuities: A Case Study in Middle–Upper Devonian Carbonate-Dominated Settings of North America

Abstract

AbstractNondepositional hiatuses tend to favor the dense accumulation of skeletal material because they are associated with minimal sedimentary dilution of bioclast input. However, bioclast durability or production must be sufficient to counterbalance the rigors of delayed burial and especially the repeated events of seafloor exposure and reworking that bioclasts can experience during sedimentary bypass or starvation associated with the formation of hiatuses. Detailed field investigations of skeletal concentrations in Middle–Upper Devonian brachiopod-rich carbonate stratigraphic records from the continental margin of Nevada and the cratonic interior of Iowa reveal a surprising lack of abundant skeletal material mantling major stratigraphic discontinuities. Rather, the distribution of densely packed brachiopod deposits tends to be determined by physical processes that operate within the timescale of deposition of a single lithofacies, producing skeletal concentrations that are mostly associated with beddin...